During operation, an operational amplifier, designed to sense a voltage signal and output an amplified voltage signal, typically is offset as a result of environmental effects. Environmental effects can vary with time. For example, the operational amplifier can warm up depending on exposure to coolant and properties of that coolant. The change in operating temperature can bring about a change of an operating point of the operational amplifier that, as a result, is offset with respect to a fixed design operating point.
In order to ensure operation of the operational amplifier according to design, the operational amplifier is biased, i.e., the amplified voltage signal is based on a superposition of the sensed voltage signal and an essentially constant bias voltage.
A difficulty is to get the bias voltage to adequately compensate effects that offset the operating point of the operational amplifier. Further, it is difficult to take account of varying environmental effects on the operation of the operational amplifier, without disrupting that operation to allow for a fresh calibration to update the bias voltage.
The elements of the drawings are not necessarily to scale relative to each other. Like reference numerals designate corresponding similar parts. Because components of embodiments according to the present invention can be positioned in a number of different orientations, directional terminology may be used for purposes of illustration that, however, is in no way limiting, unless expressly stated to the contrary. Other embodiments according to the present invention and many of the intended advantages of the present invention will be readily appreciated as they become better understood by reference to the following detailed description. It is to be understood that other embodiments may be utilized and structural or logical changes may be made without departing from the scope of the present invention. The following detailed description, therefore, is not to be taken in a limiting sense, and the scope of the present invention is defined by the appended claims.